Diagnosis, Growth and Exploitation Rate of the Sapater (Chloroscombrus chrysurus, Linnaeus 1766) Fishing by Purse Seine in the Nearshore Waters of Benin

Abstract

Chloroscombrus chrysurus (Linnaeus 1766) is one of the most abundant species of Carangidae family occurring in the nearshore waters of Benin. To ascertain the exploitation level of this fishery resource, some demographic parameters of the species were studied for management and conservation measures. 605 specimens were collected randomly from commercial catches from August to November 2014. Morphometric, meristic and weight data were analyzed using SPSS software and the ELEFAN I routine from FiSAT. The population of C. chrysurus was not heterogeneous with a sex-ratio of 1.4:1 (p < 0.05; χ² = 312.485) and masculinity and femininity rates were 58.31% and 41.69% respectively. Length frequencies showed low percentage of small sized individuals and independent distribution of sex (r = 0.16, p < 0.05). The monthly variations of the gonad-somatic index (GSI) and the condition factor (Kc) showed a decreasing trend over the review period and corresponding probably to the period of gametes emission. von Bertalanffy growth parameters estimated were L_∞ = 28.35 cm, K = 0.49 year^-1, t₀ = -0.33 year and φ’ = 2.59. Total mortality, natural mortality and fishing mortality are 1.39, 1.17 and 0.22 respectively. The exploitation rate (E = 0.16) showed that the resource was underexploited implying that the purse seine is not a danger for this species.